Self sealing charging hopper for high dump mixers



Oct. 30, 1962 1 G. HILKEMEIER SELF SEALING CHARGING HOPPER FOR HIGH DUMP MIXERS 2 Sheets-Sheet 1 Filed Feb. 26. 1960 LOUIS G. HILKEMEIER INVENTOR. BY M Oct. 3G, 1962 1 G. HILKEMEIER SELF' SEALING CHARGING I-IOPPER FOR HIGH DUMP MIXERS Filed Feb. 26, 1960 2 Sheets-Sheet 2 LOUIS G. HILKEMEIER INVENTOR. BY /4 FIG. 4

United States Patent O 3,061,232 SELF` SEALING CHARGING HOPPER FOR HIGH DUMP MIXERS Louis G. Hilkemeier, Plainfield, NJ., assiguor to Worthington Corporation, Harrison, N J., a corporation of Delaware Filed Feb. 26, 1960, Ser. No. 11,377 2 Claims. (Cl. 259-161) This invention relates to mixers, especially inclined open ended high dump type transit mixers. More particularly this invention is a means of minimizing wear on the dust seal between the rotatable charging conduit and the nonrotatable charging device of a high dump type transit mixer.

In high dump transit mixers, the mixing drum is rotatably mounted on the truck chassis and has an elevated, axial opening at the rear end through which material is charged and discharged. Spiral blading is connected to and extends inwardly from the wall of the drum. An open-ended charging conduit is mounted centrally in the drum at the rear end of the drum and the charging conduit extends partially into the central longitudinal area of the drum and is connected about the interior edge of the spiral blading. The charging conduit facilitates the entrance of concrete ingredients past the spiral blading into the interior of the drum. Associated with the charging conduit and mounted at the open upper end of the inclined drum is a charging device, usually a funnel-like hopper having a discharge end adapted to direct concrete ingredients into the charging conduit. The spiral blading when rotating in its discharge direction is arranged to discharge mixed concrete through an ejection channel described between the exterior of the charging conduit and the drum wall out the open end of the drum about the charging conduit. Thus, there are two designed paths of communication withthe interior of the drum; the rst path called the charging path is by way of the charging hopper and the charging conduit; and the'second path called the ejection path is by way of the closed ejection channel bounded by adjacent spiral blades, the drum wall and the charging conduit.

During the charging operation open end mixers have a cement dust escape problem due to the -fneness and fluidity of cement.

The dirst possible exit for the cement dust is back through the charging hopper itself via the charging path. As material is being charged the direction of iiow is into the drum, thus escape through this path is overcome and after material is charged the lid is closed. Therefore, dust escape out the charging path is simply controlled.

The ejection path is the second possible dust escape route. However, the escape of dust through the ejection path is prevented by the spiral blading which presents a circuitous ow route for the airborne cement particles to travel. The cement particles must traverse the closed ejection channel between adjacent spiral blades in order to escape between the charging conduit and the wall of the drum. Since it is conventional mixing practice to introduce water before introducing cement, the spiral ejection path generally contains water which serves as a trap for the cement dust.

` For obvious reasons, it is conventional mixer design to provide a charging hopper which doesnot rotate with the drum; therefore, during the charging operation, when the drum is rotating, relative rotation between the charging conduit and the charging hopper must be accommodated and the joint between the discharge end of the charging hopper and the charging conduit constitutes a third potential dust leakage route. Accordingly, in the joint between the discharge end of the hopper and the charging conduit a sealing structure is required which and seals the joint against high concrete level without sealing the passage between the charging conduit and the drum. The drum is rotated in one direction, called the discharge direction for ejecting mixed concrete; the direction of rotation is reversed for charging and mixing so that material will be urged down into the drum. Unless the drum is rotating in its discharge direction, the blading serves as a barrier to the concrete. Thus, the sealing structure located between the charging conduit and the charging hopper is primarily a dust seal and is therefore susceptible to relatively light design and more versatile techniques to reduce abrasion on the seal are possible.

This sealing structure is generally a rubber-like element interposed between the hopper and the charging conduit which rubber-like element is of necessity subjected to severe wear; therefore, it is conventional design practice to arrange for movement of the charging hopper between an engaged or operative position in which it contacts the charging conduit and a disengaged or inoperative position in which it is spaced away from the charging conduit. In the prior art devices engagement motion is manually controlled. Manual control of this engagement gives rise to the problem that the vulnerable sealing structure is engaged longer than is functionally necessary for the charging of materials into the drum thereby needlessly aggravating wear on the sealing structure.

The present invention overcomes the sealing structure excessive wear problem of the prior art devices by including an automatic disengagement means to disengage the sealing structure unless material is being charged into the charging conduit. The sealing structure is disposed in sealing engagement when the hopper is urged downward against the thrust of the automatic disengagement means by the weight of material in the hopper. Adjustments for the automatic disengagement means are provided so that the sealing structure will be in sealing engagement when a minimum load is in the hopper. lWhen there is no material in the charging hopper the automatic disengagement means moves the sealing structure out of engagement thereby greatly prolonging the useful life of the sealing structure.

Accordingly, the present invention comprises in combination an inclined rotatable mixing drum having a single end opening, a charging conduit disposed in the drum adjacent the open end of the drum, blade means mounted in the drum and disposed to form closed channels about said charging conduit, a charging device supported in association wit-h said charging conduit to coact with the charging conduit in charging materials into the drum as the drum rotates, the exterior end of said charging conduit and said charging device defining a relatively rotatable joint therebetween, sealing means removably disposed in sealing engagement in said joint to seal said joint when the drum is being charged, and automatic disengagement means operatively associated with said sealing means to move said sealing means out of sealing engagement when said charging device is inoperative.

Another object of the present invention is the provision of a charging hopper having a exible member attached thereto suitable for abutting the rim of the charging conduit, the flexible member thereby participating in the support of the hopper.

`Another object of the present invention is the provision of sealing means between the relatively rotatable charging conduit and charging hopper which sealing means is shielded from the flow of material being charged into the drum by a deflection means disposed inwardly of the sealing structure and extending into the charging conduit so that the sealing means is removed as effectively as possible from the path of material being charged into the charging conduit.

Another object of the present invention is the elimination of the necessity of frequent removal and replacement of worn sealing structure parts.

Another object of the present invention is the provision of a sealing structure which is so designed that replacement of any parts which might eventually wear out is facilitated so that replacement of the entire sealing structure is avoided.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims taken in conjunction with the accompanying drawings of the preferred embodiment of the invention in which:

FIGURE 1 is a rear end view of the hopper with sealing means, automatic disengagement means and associated parts installed on a transit mixer of the high dump FIGURE 2 is a side elevation view illustrating the sealing structure installed on a transit mixer of the high dump type.

FIGURE 3 is an exploded front perspective view showing the charging hopper, the sealing structure, the wings and the automatic disengagement means. The elements appear in dissembled spaced relationship.

FIGURE 4 is an enlarged Vertical sectional view of the sealing structure.

FIGURE 5 is an enlarged vertical sectional view of the automatic disengagement means.

FIGURE 6` is a fragmentary view of the mixing drum at the open end thereof.

Mixer In the drawings wherein like numerals indicate like parts, FIGURE 2 illustrates the operative association of the present invention with a mixer of the high dump type generally described 11. Mixer 11 includes rotatable mixing drum 12 mounted in the usual manner on a suitable frame 13. A driving mechanism is also provided but is not here shown. The particular type of driving mechanism is optional except that the direction of rotation must be rever-sible so that drum 12 may be driven in either direction. Drum 12 is very appropriately truncated cone shaped and is mounted sidewise with its axis 14 inclined upwardly and rearwardly to dispose its vortex 15, which is rear end 16 of drum 12, high; thereby accommodating a large supply of concrete and discharging the concrete at a higher elevation than would a comparable horizontal mixer. The high dump design employs the driving mechanism to give the mixed concrete a greater hydraulic-type head for placement.

Mounted on wall 17 of drum 12 are spiral blades 1'8. The pitch and height of blades 18 are apportioned with regard to the wall 17 slope and the inclination of drum 12 so that blades 1S will advance material up the drum 12 incline to the wall opening or open rear end 16 when drum 12 is being rotated in one direction and to urge material down into drum 12 when drum 12 rotates in the opposite direction for mixing or charging. As concrete is mixed it becomes more cohesive and has greater internal shearing strength; therefore, it becomes more easily handled by means of blade devices.

A charging conduit 19 is mounted centrally on the spiral blades 18 to afford an inlet or charging passageway 20 to the interior 21 of the drum 12. This charging conduit 19 permits the entrance of materials into the interior 21 of drum 12 without the interference of the spiral blades 18. After being mixed the concrete is ejected by spiral blades 18 out closed ejection channel 22 bounded by two adjacent spiral blades 18 such as 2'3 and 24, wall 17 of drum 12 and exterior wall 2S of charging conduit 19. Because drum 12 has a cylindrical wall portion 26 adjacent open rear end 16 which wall portion 26 is concentric about charging conduit 19, the ejection channel 22 is uniform throughout the axial length of cylindrical drum portion 26 for the uniform discharge of concrete out closed ejection channel 22. The arrangement of spiral blades 1'8 in the space between charging conduit 19 and cylindrical drum wall portion 26 permits the maintenance of high concrete levels in drum 12 without requiring a fluid seal for the passage 27 between charging conduit 19 and cylindrical drum wall portion 26.

Beneath and embracing the open rear end 16 of drum 12 is usually a discharge apron 51 supported on the fixed frame 13. Generally the discharge apron 51 is designed to be at all times in communication with ejection channel 22 between charging conduit 19 and the cylindrical wall partition 26 of drum 12 to receive material worked out of drum 12. Usually the concrete is placed by means of chutes which communicate with the discharge apron 51.

The escape of dust between charging conduit 19 and cylindrical wall portion 26 of the drum 12 requires the dust to traverse the closed ejection channel 22 formed by two adjacent blades such as 23 and 24, between cylindrical wall portion 26 of drum 12 and charging conduit 19. Since it is conventional practice to add water before introducing cement, the water in closed ejection channel 22 serves as a trap for cement dust.

Charging Device In loading drum 12, the materials are inserted through charging conduit 19 into interior 21 of drum 12. To facilitate such loading, a charging device shown in FIG- URES l, 2 and 3 as hopper 2S is mounted on frame 1`3 of mixer 11. As shown in FIGURE 2, discharge end 29 of charging hopper 28 communicates with charging passageway 20. Truck mixers are generally loaded with stone, sand and cement by gravity flow from high dispensing hoppers. A certain amount of truck maneuvering is generally necessary to position the truck for reception of the materials. Hopper 28 permits the downward fall of the materials being charged into mixer 11 and reduces the accuracy required in positioning the truck to receive the concrete ingredients.

As shown in FIGURES 2 and 3 hopper 28 is pivotally mounted `at open rear end 16 of drum 12 by means of pins 30, 31, and is able to rotate in a vertical arc about those pins 30, 31. Hopper extension 32 connected to hopper 28 at 33 is smaller in diameter than exterior end 34 of charging conduit 19 so that hopper extension 32 can be inserted and removed from charging passageway 20 by the rotation of hopper 2S about pins l30, 31. Flange 35 is connected 4to hopper extension 32. Rubber seal 36 is connected to flange 35 and is aligned for abutting contact with exterior end 34 of charging conduit 19 to provide a sealing and bearing contact of hopper 28 against exterior end 34 of charging conduit 19.

As shown in FIGURE 2, hopper extension 32 serves as a deflecting means keeping ythe joint between seal 36 and exterior end 34 of charging conduit 19 out of direct contact with material being charged into drum 12.

Stiff cantilevered wings or positioning members 38, 39 are rigidly connected to project llaterally from charging hopper 28. Symmetrical holes 40 are formed in wings 38, 39 to receive bolts `41, 42 which align springs 43, 44 and are connected to frame 13 at 45, 46. Springs 43, 44 are aligned and operable in opposition to the weight of hopper 28 including the contents thereof to tend hopper 28 toward rotation about pins 30, 31 away from sealing engagement with charging conduit 19.

Threads 47, 48 are provided on bolts 41, 42 to permit the adjustment of springs 43, 44 to disengage seal 36 from'exterior end 34 of charging conduit 19 when hopper 28 is empty. Lock nuts 49, 50 are provided to maintain spring y43, 44 settings constant. Angle 52 shown in FIG- URES 2 and 5 is adjustably mounted on frame 13 in limiting the travel of hopper 28. The space x between the wings and angles 52 limit the hopper 28 from bouncing in transit thereby protecting seal 36.

Operaton The thrust of spr-ings 43, 44 maintains seal 36 in a normally disengaged position out of contact with exterior end 34 of charging conduit 19. When material is being charged into drum 12 through hopper 28 the weight of 'the material in hopper 28 tends hopper 28 to revolve about pins 30, 31 and is transmitted by means of wings 38, 39 to bear upon springs 43, 44 thereby overcoming the thrust of springs y43, 44 depressing springs 43, 44 and causing the'hopper 28 to rotate toward open rear end 16 of mixer -11 until seal 36 cornes into abutment between ilange 35 and exterior end 34 of charging conduit 19. Thus, seal 36 is automatically operable when charging hopper 28 is in use. When the weight of material in charging hopper 28 is reduced by the emptying of the contents from charging hopper 28 in-to charging conduit 19, the weight transmitted from charging hopper 2S to springs 43, 44 is reduced and springs 43, 44 extend thereby rotating hopper 28 away from open rear end 16 of mixer 11 and disengaging seal 36 from exterior end 34 of charging conduit 19.

It will be understood that changes may be made in the details of construction and in the correlation of the Various elemen-ts of the sealing and disengaging means to accomplish the same results without departing from the spirit of the present invention or the scope of the claims. The abutting flange seal 36 with a spring automatic disengagement means is shown because of its `simplicity and practicality; however, many more elaborate equivalences become obvious to those familiar with the mixing art. For example, the seal 36 could be a pneumatic or a shutter type of device. The automatic disengagement device might be operable in response to various other kinds of signals. Springs 43, 44 could be replaced by resilient torsion elements. These and other similar equivalences .although presently believed to be less desirable than the above outlined embodiment are clearly within the perview of the present disclosure.

What is claimed is:

1. A -device for automatically sealing the charging hopper during charging of a rotatably mounted mixing drum comprising, a frame to support said mixing drum, said mixing drum having an inclined axis and a charging passageway about said axis at the upper end of said mixing drum, said mixing drum adapted to rotate about the axis, at least one spiral mixing blade mounted in said mixing drum, a charging conduit disposed in said wall opening of said mixing drum to form a closed channel in said wall opening bounded lby said mixing blade land said charging conduit, said charging hopper mounted on said frame to extend into said charging conduit, sealing means connected to the outer diameter of said charging hopper and .adapted to abut said charging conduit to form a sealed connection therewith, resilient means to connect said charging hopper and said frame, said resilient means normally separating said sealing means from said charging conduit and adapted to yield on said charging hopper being charged to permit said sealing means to abut said charging conduit to form a sealed connection therebetween.

2. The combination claimed in claim 1 wherein said charging hopper rotatably mounted on said frame, an extension connected to the end of said charging hopper adjacent said charging conduit, a ange formed on the outer diameter of said charging hopper yadjacent said charging conduit and inward of the edge of said extension, sealing means mounted on said flange and adapted to abut said charging conduit to form a sealed connection therewith, positioning means mounted on said charging hopper, and resilient means to adjustably connect said positioning means of said charging hopper and said frame.

References Cited in the le of this patent UNITED STATES PATENTS 2,264,039 Hoya Nov. 25, 1941 2,489,885 Henderson et al Nov. 29, 1949 2,574,184 Jaeger Nov. 6, 1951 2,688,472 Lendved et al. Sept. '7, 1954 2,692,765 Gerst Oct. 24, 1954 2,723,112 Smith Nov. 8, 1955 2,854,224 Broberg Sept. 30, 1958 2,883,166 Hilkemeier Apr. 21, 1959 2,884,235 Broberg Apr. 28, 1959 2,902,268 Broberg Sept. 1, 1959 2,904,318 Broberg Sept. 15, 1959 

